Droid Razr Maxx screen goes dark

HI all,
Recently my Razr Maxx goes into a sleep mode(especially after sitting ) and its next to impossible to wake some times the home screen appears after 10 secs sometimes right away.
My phone is not rooted and I did not re-install any launchers after the last factory reset does anyone know of any setting that might control this or is a replacement phone in order?